Trichomonas vaginalis antigens in vaginal and urine specimens by immunochromatography, compared to culture and microscopy

ABSTRACT

This study evaluated the immunochromatographic [1C] capillary flow technology for detection of T. vaginalis antigens in vaginal and urine specimens. The 1C antigen-detection test and microscopy wet smears were assessed against the InPouch TV culture. Vaginal-swabs and first-voided urine specimens were obtained from 348 sexually active symptomatic or asymptomatic, >/= 16 years old women. Nineteen samples [5%] were positive by culture [95%, CI 0.3-0.8]. The 1C test [vaginal-specimens] was more sensitive than the wet smears. 1C sensitivity was 84% [95%CI, 0.68-1.01], specificity 98% [95%CI, 0.96-0.99], positive predictive value [PPV] 70% [95%CI, 0.51-0.88], negative predictive value [NPV] 99% [95%CI, 0.98-1], [positive likelihood ratio [+LR] 39.6, and negative likelihood ratio [-LR] 0.2. The 1C test using urine as a substrate had less performance than both microscopy and 1C .test of vaginal specimens. Urine-IC sensitivity was 53% [95%CI, 0.30-0.75], specificity 99% [95% CI, 0.98-1.00], PPV 77% [95%CI, 0.54-1], NPV 97% [95%CI, 0.96-0.99], +LR 57.7, and -LR 0.5. Sensitivity of vaginal smear was 68% [95%CI, 0.48-0.89], specificity 100%, PPV 100% [95% CI, 1], NPV 98% [95% CI, 0.97-1], +LR>225, and -LR 0.3. T. vaginalis was diagnosed in two wet urine samples, but not in smears. The 1C antigen improved T. vaginalis diagnosis, especially in screening, rapid, or point-of-care test, but in urine was less reliable than with vaginal smear